The El Soplao Konservat-Lagerstätte: a key Cretaceous amber deposit from Spain

The Early Cretaceous (Albian) El Soplao Konservat-Lagerstätte, from Cantabria (northern Spain), provides unparalleled insights into late Mesozoic terrestrial ecosystems. The site stands out for yielding amber pieces with a blue–violet hue and abundant bioinclusions, which document a remarkably diverse arthropod assemblage. Many fossils exhibit anatomical fidelity down to microscopic structures, allowing detailed morphological and palaeoecological investigations. El Soplao amber preserves the oldest representatives of several major arthropod groups as well as compelling evidence, often direct, of behaviours and symbiotic interactions along the parasitism–mutualism spectrum between arthropods, insects and plants, and arthropods and vertebrates. Ongoing multidisciplinary research keeps expanding the palaeobiological knowledge on this remarkable locality, which represents one of the most important fossiliferous amber deposits in Europe.